Circuit interrupter with improved contact means,arc-box structure and terminal means



Nov. 3, 1970 s. A. MRENNA 3,538,287

CIRCUIT INTERRUPTER WITH IMPROVED CONTACT MEANS,

ARC-BOX STRUCTUREAND TERMINAL MEANS Filed May 31, 1968 5 Sheets-Sheet 1 Stephen A Mrenna ATTORNEY Nov. 3, 1970 s. A. MRENNA 3,538,287

CIRCUIT INTERRUPTER WITH IMPROVED CONTACT MEANS, ARC-BOX STRUCTURE AND TERMINAL MEANS Filed May 51, 1968 3 Sheets-Sheet 2 s. A. MRENNA 3,538,287 CIRCUIT INTERRUPTER WITH IMPROVED CONTACT MEANS,

Nov. 3, 1970 v ARC-BOX STRUCTURE AND TERMINAL MEANS- Filed May 31. 1968 I5 Sheets-Sheet 5 United States Patent 3,538,287 CIRCUIT INTERRUPTER WITH IMPROVED CON- TACT MEANS, ARC-BOX STRUCTURE AND TERMINAL MEANS Stephen A. Mrenna, Beaver, Pa., assignor to Westinghouse Electric Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed May 31, 1968, Ser. No. 733,604 Int. Cl. H01h 1/50, 9/30 U.S. Cl. 200-170 9 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION AND PRIOR ART It is desirable, for certain applications in the circuitinterrupter art, to provide a plurality of contact points between the cooperating contact structures. This type of. contactmeans is disclosed, for example, in the patents to Musgrave, No. 1,935,516, Massey, No. 1,967,623 and Rankin, No. 2,222,722. This invention is an improvement over the prior art of the type disclosed in the abovementioned patents in that the contact meansof this invention is a compact, simplified, readily-assembled, reliable structure that is constructed such that the width-wise dimension thereof is kept reduced to enable the construction of a relatively inexpensive and compact circuit interruptenAn improved arc-box is supported on the stationary contact structure in a novel manner, and the widthwise dimension of the combination of the arc-box and stationary contact structure is kept reduced.

For certain applications in the switchgear art, it is desirable to provide a bolt-type pressure connection between a blade conductor anda terminal plate. For example, it is desirable in the higher ratings to be able to bolt a fuse stab to a'terminal plate to provide a secure connection andincreased contact pressure. An object of this invention is to provide an improved terminal means for connecting a blade-type conductor, such as a fuse stab, to a terminal plate.

SUMMARY OF THE INVENTION- An improved circuit-interrupting device comprises an enclosure and an externally operable multi-pole circuit interrupter. supported in the enclosure. The multi-pole circuit interrupter is a fused switch with each pole unit comprising cooperable contact means'and a fuse connected in electrical series with the contact means. Each of the contact means comprises a stationary contact structure and a movable contact structure cooperable with the stationary contact structure. The stationary contact structure comprises a conducting main contact member, comprising a generally planar main body plate part, and a pair of secondary contact members on opposite sides of the main body plate part with securing means drawing the back portions of the secondary contact members against the opposite sides of the main body plate part to fixedly mount the secondary contact members on the 3,538,287 Patented Nov. 3, 1970 "ice main body plate part. Spring means may also be provided on the outer sides of the secondary contact members and secured by the securing means, to the secondary contact members and main body plate part to provide increased contact pressure. The movable contact structure comprises a pair of spaced generally parallel contact blades. In the closed position of the contacts, the pair of spaced contact blades are positioned on opposite sides of the main body plate part with each of the contact blades being positioned between the associated side of the main body plate part and a contact portion of the associated secondary contact member. In the disclosed embodiment, each of the secondary contact members comprises three contact fingers for engaging the associated movable contact blade, and each a movable contact blade part is provided with a cont-act surface for engaging the associated side of the main body plate part so that eight contact points are provided between the stationary contact structure and the movable contact structure. With'the second ary contact members, and also the spring means, secured to a generally planar main body plate part by means of securing means that draws these parts together, a compact, simplified, readily-assembled and reliable contact structure is provided .with the contact structure being constructed such that the widthwise dimension thereof is kept reduced. A novel insulating arc-box is supported on the stationary contact structure and connected to the stationary contact structure by cooperating-slot means and by means of a securing means that extends transversely through the generally planar main body plate part of the stationary contact structure to effective y secure the arcbox to the stationary contact structure and to provide an improved combinaion of an arc-box and stationary contact structure that is constructed with a reduced widthwise dimension.

Improved terminal means is provided for securing a fuse blade to a terminal plate. An elongated pressure plate member is secured to the terminal plate at one end thereof by means of a EfilSt adjustable securing means. A second adjustable securing means is mounted on the terminal plate, and with the fuse blade in position the pressure plate member can be rotated about the first adjustable securing means to a pre-connected position cooperating with the second adjustable securing means. In the preconnected position, the fuse blade is positioned between the contact face of the terminal plate and the pressure plate member so that as the first and second adjustable securing means are tightened, an effective pressure connection is made between the fuse blade and the terminal plate. When it is desired to remove or replace the fuse,

both of the adjustable securing means are loosened, and

the pressure plate member is rotated about the first adjustable securing means to the open position to permit re-'" moval of the fuse blade. In the described embodiment, each of the adjustable securing means comprises bolt means secured to the terminal plate, and the pressure plate member is provided with a hook-shaped end for.

moving into and out of the pre-connected position.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view, with parts broken away, of a. multi-pole circuit interrupting device constructed in ac-- cordance with principles of this invention;

, FIG. 2 is a side elevational view of the circuit interrupting device of FIG. 1;

FIG. 3 is a plan view, with parts in section and with shown on an enlarged scale- FIG. 5 is a perspective view illustrating the stationary contactstructure-and conducting plate seen in- FIGS.

line VIII-VIII of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, there is disclosed, in FIGS. 1 and 2, a circuit interrupting device 5, comprising an enclosure 7 and an externally operable circuit interrupting device 9 supported in the enclosure 7. The enclosure comprises a receptacle part 11 and anopenable cover 13 supported onthe receptacle part 11 for movement about hinges 15. v

The circuit interrupter 9 is a three-pole circuit interrupter comprising a switch part 17 and a fuse part 19. The switch part 17 comprises contact means 21 for each pole and a common externally operable operating mechanism 23 for simultaneously operating the three pole units.

The operating mechanism 23 comprises an elongated handle lever 25 that is fixed at the inner end thereof to a rod 29 that extends through an opening in the side wall of the receptacle. The lever 25 moves within a metallic hood 31 that is supported on the external side of the receptacle. The lever 25 is pivotally movable to pivot an operating plate 33 that is pivotally mounted for movement about the same axis as the rod 29 and that is pivotally connected to a spring support 35 by means of a pivot pin 37. A pair of compression springs 39 are mounted on a pair of rods 41 that extend from the spring support member 35 and that are positioned in openings in a spring-support bracket 43 that is mounted for movement about a pivot pin 44. The operating plate 33 is provided with a pair of connecting arms 45 that are positioned on opposite sides of a downwardly extending leg of an elongated operating rod 47. The operating rod 47 is an inverted generally U-shaped rod that is mounted at the inner ends of the legs thereof for pivotal movement about the same axis as the rod 29. A pair of stop members 49 are provided to limit movement of the operating rod 47 in both of the operating position of the rod 47.

7 An elongated U-shaped rigid insulating member 51 is positioned on the rod 47, and in each pole unit a connecting arm 53 receives the insulating member 51 in opening 55 to operatively connect the connecting arm '53 to the operating rod 47 (FIG. 4).

Referring to FIGS. 3, 4 and 7, the movable contact support 53 is connected to a movable contact structure, indicated generally at 59, by means of a pair of rivets 61. The movable contact structure 59 comprises a pair of the spaced contact blades 63 (FIG. 7) having contact surfaces 64 on the inner faces thereof. The contact blades 63 are pivotally mounted on a conducting plate 65 by means of a bolt 67. The bolt 67 passes through suitable slots in the contact blades 63 and through a suitable opening in the conductingplates 65, and a pair of spring washers 69 are provided on the outer sides of the contact blades 63. A nut 71 is threaded on one end of the bolt 67. When the bolt means 67, 71 is tightened, the spring washers draw the contact blades 63 against the opposite flat sides of the conducting plate 65 to provide contact pressure between the contact blades 63 and the opposite faces of the conducting plate 65 while permitting pivotal movement of the movable contact structure about the axis of the bolt 67 on the stationary conducting plate 65.

Ascan be seen in FIG. 4, the conducting plate 65 comprises a flat planar upstanding main-body part 75 that is bent-over at the lower end thereof to provide a planar supporting flange 77 that rests on an insulating support 79. A-pairof bolts 81- are threaded-into tapped openings in the supporting flange or leg 77 to fixedly mount the conducting plate 65 on the insulating support 79. The insulating support 79 is fixedly secured to the base of the receptacle by means of a pair of bolts .83. Another rigid conducting plate 85 (FIGS. 3-6) comprises a flat planar upstanding main body plate part 87 that is bent-over to provide a lower planar supporting flange 89 that rests on the insulating support 79. A pair of bolts 91 extend into tapped openings in the supporting flange 89 to fixedly mount'the conducting plate 85 on the insulating support 79. As will be understood with reference to FIG. 5, one end of the main-body part 87 of the conducting plate 85 serves as a main contact member of a stationary contact structure indicatedgenerally at 97.

The stationary contact structure 97 comprises the main contact member 87, a pair of secondary contact members 99 (FIGS. 5 and 6) and a pair of spring members 101. As will be understood with reference to FIGS. 4-6, each of the secondary contact members 99 comprises a generally resilient conducting member that is formed to provide three separate fingers at the upper or front-end thereof and a support part at the back end thereof. The fingers are bent over to provide contact portions shown at 103 in FIG. 6. Each of the spring members 101 comprises three finger portions at the upper or front end there of and a support portion at the back end thereof. A pair of bolt members 107 extend through suitable openings in the support parts of the springs 101, the support parts of the secondary contact members 99 and the main contact member 87, and a pair of nuts 109 are threaded onto the bolts 107 to draw the members 101 and 99 inward against the opposite fiat sides of the main contact member 87 to fixedly mount the secondary contact members 99 and springs 101 on the main contact member 87.

The circuit interrupting device is shown in FIGS. l-4 in the open or off position. When it is desired to close the circuit interrupting device, the external handle lever 25 is pivoted clockwise (FIGS. 2 and 4) to the closed or on position. During this movement, one of the clawrnernbers 45 of the operating plate 33, engaging the one downward extending leg of the inverted generally U- shaped operating rod 47, moves the operating rod 47 clockwise about the axis of the rod 29 (FIG. 2), and with the rod 47 and insulating member 51 captured in the opening 55 (FIG. 4) of the contact support member 53, this movement moves the contact support member 53 to thereby pivot the movable contact structure 59 clockwise (FIG. 4) about the axis of the bolt 67 from the off or open seen in full lines in FIG. 4 to the on or closed position seen in broken lines in FIG. 4. As can be understood with reference to FIG. 2, the over-center compression springs 39 serve to close the circuit interrupter with a snap-action. The operating lever 33 and spring support 35 serve as a toggle, and as the operating member is moved to the on position the toggle 35, 33 is erected compressing the springs 39 during the first half of this movement and thereafter the compressed springs 39 discharge to collapse the toggle 33, 35 in the opposite direction with a snap-action forcing the operating lever 33 to the closed position with a snap-action.-

The parts are stopped in the closed position when the rod 47 engages one of the stop members 49.

The switch is opened by reverse movement of the operating handle lever 25 to move the operating lever 33 in a counterclockwise (FIG. 2) direction to erect the toggle 33, 35 during the initial part of the movement so that when the toggle 33, 35 goes over-center the compressed springs 39 will move the operating lever 33 to the offv or open position with a snap-action. During movement of the operating lever 33 to the open position, the other of the claw-members 45 (FIG. 1) engages the downwardly extending arm of the inverted generally U-shaped operating rod 47 to pivot the operating rod 47 counterclockwise about the axis of the rod 29 (FIG. 2) to move the movable contact structure 59 from the on or closed position seen in broken lines in FIG. 4 to the off or open position seen in full lines in FIG. 4. Movement to the open position is stopped when the operating rod 47 engages the other stop member 49 as seen in FIG. 1.

' As can be understood with reference to FIGS. 37, the spaced contact blades 63 (FIG. 7) move against the opposite sides of the main contact member 87, and each of the contact blades 63 moves between the associated side of the main contact member 87 and the spring fingers of the associated secondary contact 99. The widthwise dimension of the main contact member 87 is greater than the dimension between the contact surfaces 64 (FIG. 7) so that as the contact blades 63 are moved into the closed position the contact blades 63 are forced apart. The contact blades 63 are constructed of a material with some resilience so that as the contact blades 63 are forced apart the resilience of the contact blades 63 serves to provide contact pressure between the contacts 64 (FIG. 7) and the contact portions (at the opposite flat sides of the member 87) of the main contact member 87 that are engaged by the contact surfaces '64. The dimension between each of the contact surfaces 103 (FIG. 6) and the associated side of the main contact member 87 in the open contact position is less than the effective width-wise dimension of the associated movable contact blade 63 (the dimension between the contact surface 64 and the opposite side of the contact blade 63) so that as each contact blade 63 moves between the associated secondary contact member 99 and the associated side of the main contact member 87, the associated secondary contact member 99 is forced outwardly such that the resilience of the associated contact member 99 and spring 101, serve to bias the contact surfaces 103 (FIG. 6) of the contact fingers against the outer side of the associated contact blade 63 to provide contact pressure between the contact surfaces 103 and the contact blade 63. The resilience of the contact members 99 and the bias of the springs 101 also operate against the contact blades 63 to provide increased contact pressure between the contact surfaces 64 (FIG. 7) and the opposite sides of the main contact member 87. As can be understood with reference to FIGS. and 6, the upper ends of the secondary contact members 99 are flared out to guide the contact blades 63 into position during closing operations of the circuit interrupter.

An insulating arc-box indicated generally at 115 (FIGS. 3 and 4) is fixedly mounted on the conducting plate 85. As can be seen in FIG. 5, the main-body part of the conducting plate 85 is provided with a slot 117 therein, and there is a tapped opening 119 in the main-body part below the slot 117. The arc-box 115 (FIGS. 3 and 4) is a molded generally U-shaped insulating member having a slot in the bight portion 121 thereof'in proximity to the back of the arc-box 115. As can be seen in FIG. 3, the upper portion of the arc-box 115 is broken away to expose a cavity at the back portion thereof that receives a bolt 123. The cavity is provided with a shoulder portion 124 that is engaged by a washer 125. Referring to FIG. 4, it will be noted that the arc-box is placed in position with the bightportion 121 thereof extending downward into the slot 117 (FIG. 5) of the conducting plate '85 and with the slot in the back portion of the bight portion 121 straddling the opposite sides of the conducting plate 85 below the slot 117. With the arc-box 115 in this position, the bolt 123 (FIG. 3) is placed into the cavity in the lower portion of the arc-box with the washer 125 engaging the shoulder 1240f the arc-box, and the bolt 123 is threaded into the tapped opening 119 (FIG. 5) to draw the arc-box 115 against the one side of the conducting plate 85 to fixedly mount the arcbox 115 on the mounting plate 85. With the bight portion 121 in the slot 117; with the slot at the back of the bight portion straddling the plate below the slot 117; and with the mounting bolt 123 fixedly secured in position; the arc-box is fixedly mounted on the conducting plate 85. The arc-box 115 is a U-shaped arc-box molded to form a pocket 126 (FIGS. 3 and 4) between the legs thereof. As can be understood with reference to FIGS. 3 and 4, the movable contact blades of the movable contact structure 59 move in the pocket 126 between the legs of the U-shaped arc-box 115, and the movable contact structure engages the stationary contact structure in the pocket 126.

With the circuit interrupter in the closed position, the circuit through each pole unit extends from a solderless terminal connector 129 (FIGS. 3 and 4), that is secure d to the conducting plate 85 by bolt means 131, through the conducting plate 85, the stationary contact structure 97, the movable contact structure 59, the conducting plate '65, a fuse indicated generally at 135, a U-shaped terminal plate 137 to another solderless terminal structure 139 that is secured to the U-shaped terminal plate 137 by bolt means 141. The U-shaped terminal plate 137 is fixedly mounted on an insulating block 142 by bolt means 143. The insulating block 142 is fixedly secured to the base of the receptacle by bolt means 144. As can be understood with reference to FIGS. 3 and 4, the fuse is provided with a pair of flat, stab or plate terminals 145 and 147 at the opposite ends thereof for connecting the fuse in the circuit.

Improved means is provided for connecting the fuse blades 145, 147 to the associated flat conductors. Referring to FIGS. 3, 4 and 8, it will be noted that the blade conductor 147 is positioned along side a fiat face of the one leg of the U-shaped terminal plate 137. An elongated rigid metallic pressure plate 151 is supported on the plate 137 on the opposite side of the blade conductor 147. A first adjustable securing means or a bolt 153 secures the bottom of the pressure plate 151 to the conducting plate 137, and a second adjustable securing means or bolt 155 secures the front of the pressure plate 151 to the conducting plate 137. As will be understood with reference to FIG. 8, the bolt 153 extends through an opening in the pressure plate 151 and is threaded into a tapped opening in the conducting plate 137. The bolt 155 extends through a slot 157 at the front part of the pressure plate 151 and is threaded into a tapped opening in the conducting plate 137. As will be understood with reference to FIG. 4, the slot 157 is open at the side of the pressure plate 151 so that the front portion of the pressure plate comprises a hook-type structure that is hooked over the shank of the bolt 155. Suitable washer means (FIG. 8) are provided between the heads of the bolts 153, 155 and the pressure plate 151. With the bolts 153, 155 in the tightened securing position seen in FIG. 8, the bolts draw the pressure plate member 151 against the blade 147 to sandwich the blade 147- between the pressure plate 151 and the conducting plate 137 to fixedly pressure-connect the blade 147 to the conducting plate 137. When it is desired to remove the blade 147, the bolts 153 and 155 are loosened and the pressure plate 151 is pivoted about the shank of bolt 153 to the open position seen in FIG. 4. The blade 147 may then be removed. When it is desired to again connect the blade 147 to the conducting plate 137, the pressure plate member 151 is pivoted about the shank of the bolt 153 to a preconnected position wherein the shank of the bolt 155 is positioned within the slot 157. Thereafter, the bolts 153 and 155 are tightened to again fixedly pressure-connect the blade 147 to the conducting plate 137. As can be understood with reference to FIG. 4, there is a separate pressure-plate 151 similarly positioned at the other side of the fuse to pressure-connect the blade 145 to the conducting plate 65.

I claim as my invention:

1. A circuit interrupter comprising a stationary contact structure and a movable contact structure cooperable with said stationary contact structure,'said stationary contact structure comprising a conducting main contact member, said conducting main contact member comprising a generally planar main body plate part, a secondary contact means on each of two opposite sides of said main body plate part, each of said secondary contact means comprising a back mounting part and a front contact part, mounting means drawing said back mounting parts against the opposite sides of said main body plate part to fixedly mount said secondary contact means on said main body plate part, said front contact parts positioned adjacent opposite sides of said main body plate part and resiliently urged toward said opposite sides of said main body plate part, said movable contact structure comprising a pair of spaced generally parallel contact blades, means for moving said movable contact structure between a closed position wherein said movable contact structure is engaged with said stationary contact structure and an open position wherein said movable contact structure is disengaged from said stationary contact structure, in the closed position of said movable contact structure said pair of contact blades positioned on opposite sides of said main body plate part and each of said contact blades positioned between the associated side of said main body plate part and the front contact part of the associated secondary contact means, an insulating arcbox formed with a pocket therein, mounting means mounting said insulating arc-box on said conducting main contact member, and in the closed position of said movable contact structure said movable contact structure engaging said stationary contact structure in said pocket. 2. A circuit interrupter according to claim 1, each of said secondary contact means comprising a plurality of contact fingers resiliently urged toward the associated side of said main body plate part to resiliently engage the associated contact blade in the closed position of said contacts.

3. A circuit interrupter according to claim 1, each of said secondary contact means comprising a separate secondary contact member and a separate spring member engaging the associated secondary contact member to bias the associated secondary contact member toward the associated side of said main body plate part to thereby provide contact between the associated secondary contact member and the associated contact blade.

4. A circuit interrupter according to claim 1, said conducting main contact member comprising said main body plate part and being bent over at the back thereof to provide a supporting flange part, an insulating support member, and securing means securing said supporting flange part to said insulating support member to support said stationary contact structure on said insulating support member.

5. A circuit interrupter comprising a stationary contact structure and a movable contact structure cooperable with said stationary contact structure,

said stationary contact structure comprising a conducting main contact member, said conducting main contact member comprising a generally planar main body plate part, a pair of secondary contact members on opposite sides of said main body plate part, securing means securing said secondary contact members to said opposite sides of said main body plate part, each of said secondary contact members comprising a stationary secondary contact surface adjacent the associated side of said main body plate part, said stationary secondary contact surfaces resiliently urged toward said main body plate part,

said movable contact structure comprising a pair of generally parallel movable contact blades, each of said movable contact blades comprising a movable contact surface facing the other of the movable contact blades, means for moving said movable contact structure between open and closed positions relative to said stationary contact structure,

in the closed position of said movable contact structure said pair of movable contact blades positioned on opposite sides of said main body plate part with each of said movable contact surfaces engaging the associated side of said main body plate part and with each of said movable contact blades positioned between the associated side of said main body plate part and the associated contact surface of the associated secondary contact member,

means supporting said movable contact blades in a generally parallel relationship with the dimension between said movable contact surfaces being less than the dimension of the thickness of said main. body plate part when said movable contact structure is in the open position whereby said movable contact blades are forced apart to provide contact pressure between said movable contact surfaces and said main body plate part in the closed position of said contacts,

means supporting said secondary contact members such that in the open position of said movable contact structure the dimension between each of said secondary contact surfaces and the associated side of said main body plate part is less than the effective width of the associated movable contact blade whereby said secondary contact members are resiliently urged apart to provide contact pressure when said movable contact structure is moved into the closed position,

an insulating arc-box formed with a pocket therein,

mounting means mounting said insulating arc-box on said main body plate part, and in the closed position of said movable contact structure said movable contact structure engaging said stationary contact structure in said pocket.

6. A circuit interrupter according to claim 5, said conducting main contact member comprising said main body plate part and bent-over to provide a generally planar supporting flange that extends along a plane generally normal to the plane of the main body plate part, insulating support means, and securing means securing said supporting flange to said insulating support means to thereby mount said stationary contact structure on said insulating support means.

7. A circuit interrupter comprising a stationary contact structure and a movable contact structure cooperable with said stationary contact stucture, said stationary contact structure comprising a conducting generally flat main body plate part, said main body plate part comprising a generally planar stationary contact face,

an insulating arc-box comprising an insulating member having a pocket formed therein, means supporting said arc-box on said main body plate part and securing said arc-box to said main body plate part with said stationary contact face positioned in said pocket, said movable contact structure comprising a movable contact blade supported for movement along a plane generally parallel to said stationary contact face,

said movable blade being movable from an open position spaced from said main body plate part to a closed position along side said stationary contact face engaging said stationary contact face in said pocket.

8. A circuit interrupter according to claim 7, insulating support means, said main body plate part being bentover to form a generally planar supporting flange in proximity to the back thereof which supporting flange extends along a plane generally normal to said main body plate part, securing means securing said supporting flange to said insulating means to thereby support said stationary contact structure and said arc-box on said insulatingv means.

9. A circuit interrupter according to claim 8, said prising a generally U-shaped structure comprising abight' portion and a pair of opposite legs forming said pocket therebetween, said bight portion having a slot therein open at the back thereof, said arc-box positioned on said main body plate part with said bight portion positioned in said slot of said main body plate part and with the slot in said bight portion straddling said main body plate part below the slot of said main body plate part, said main body plate part having a tapped opening therein, said securing means comprising a bolt member, said arc-box having opening means therein for receiving said bolt member, and said bolt member extending transverse to said contact face and positioned in said opening means of said arc-box and threaded into said tapped opening in said main body plate part to fixedly secure said arebox on said main body plate part.

References Cited UNITED STATES PATENTS US. Cl. X.R. 

